Mixing machine



July 24, 1934.

D. DE FL CRANDELL El AL MIXING MACHINE 2 Sheets-Sheet Filed Sept. 8, 1931 y 4- DE r-.. CRANDILILL El AL 1,967,291

MIXING MACHINE Fil ed sept'. 8. 1-931 2 Sheets-Shela:

menacing 24, 1934 guns!) STATES PATENTOFFICE.

1,961,291 v I We mom Dean De Forest Grandell, Buffalo, and any Neher, Clarence Center, N. Y., assign orsto.

National Gypsum Company, Buflalo, N..Y., a corporation of Delaware Application September 8, 1931, SerialNo. 581,580 12 Claims. (01. 259-11) This invention relates to a machine for mixing solid materials and more particularly to materials which differ-considerably asto either their stickiness or as to their liquid content.

' '5 The principal object of the invention is to en- 16" disclosed in detail .in the herein'patent specification wherein,

In the accompanyin drawings: Figure 1 is a fragmentary side elevation of the 20' Figure 2 is a fragmentary, vertical, longitudinal section thereof taken on line 2-2, Fig. 3.

Figures 3 and 4 are fragmentary, vertical, transverse sections through the mixing machine taken 'on correspondingly numbered lines of 11s. 1. In the following description, similar characters of reference indicate like parts in the several figures of the drawings. 7 My invention may be embodied in various forms l-and in mixing machines of different constructions, and the present application is therefore to be regarded merely as one organization which satisfactorily carries out the inventionin practice. As here shown, the same is constructed as 351 follows: 4

Upon' a mainframe 10 isiournaled, at 11, a belt pulley 12 upon whoa periphery travels the tail end of an endless conveyor belt 18. The upstretch of this conveyor belt is suitably sup- 40. ported at closely spaced intervals by a plurality of upper, belt supporting idlers or rollers 14 which are suitably journaled at their opposite ends (in the usualand well known manner) inthe main frame 10 of the machine. The conveyor belt 46' 13 is adapted to be power driven in any suitable' -conveyor belt.

This charging box 15 is adapted to be supplied with dry. pulverized gypsum. by any suitable means such as by a spiral screw conveyor 21 which is power driven (preferably synchronously with the conveyor belt) and pushes or propels the dry gypsum rearwardly through the screw conveyor casing 22 into a vertical, discharge pipe 23 from whence it issues downwardly to the interior of aforesaid charging box 15. The latter is vertically adjustable relatively to the main frame 10 for reasons hereinafter to be given, being secured at its vertical longitudinal sides 16 by bolts and wing nuts 24 to upright supports or posts 25 which are constructed of flat bar steel and are bent outwardly at their lower ends and secured by bolts 26 to the main frame 10. The bottom edge 27 of said charging box 15 is spaced some distance above the upper surface of the upper stretch of the conveyor belt 13, this arrangement being'rendered necessary by reason of the construction illustrated is preferred in which a pair of vertical, longitudinal edging plates 28 are employed, the same being constructed of stiff but'soft material (such as leather belting or cotton webbing) and positioned against the inner faces of the side walls 16 of the charging box 15 and vertically adjustable relatively thereto by means, of bolts and wing nuts 30 which are received in vertical slots 31 formed in said side walls 16. Said edging plates 28 are normally so adjusted vertically that their lower edges are in close proximity with the upper surface of the Hinged horizontal at 32 to the front wall 1'? of the charging box 15 is a safety door 33, whose lowerportion is normallyand resiliently urged rearwardly against the front end of said charging box by a pair of tension springs 34, the front end of said springs being connected at 35 with said safety door while their rear ends are connected at 36 to the side walls 16 of said charging box. Detachably secured by bolts 3'7 to the lower front face of said door 33 is a two-edged comb 38 (see Figs. 3, 1 and 2), constructed of a rectangular plate of metal having its-opposite longitudinal edges provided with serrations or comb teeth, the one set 40 of whichis of fine pitch while the other'set41 is of coarse pitch. 110

The particular comb teeth which are adjacent the conveyor belt 13 are the ones in operative position. In the drawings the coarse comb teeth 41 are shown lowermost, but if it is desired to use the fine c'omb teeth 40 then it is merely necessary to remove the holding bolts 3'? and reverse the position of the comb 38 so that the fine teeth 40 are disposed at the lower edge of said comb, after which said bolts 37 are replaced 1nd tightened up. Said bolts pass through vertical slots 42 in the comb so that the latter may be adjusted vertically relatively to the door 33, thereby enabling the comb to be moved closer to or further away from the upper surface of the conveyor 13.- As the upper stretch of the latter moves forwardly, the dry, pulverized gypsum 20 in the charging box 15 is withdrawn upon said belt in the form of a gypsum ribbon 39, the upper surface of which is provided with the longitudinal ridges 43 while between said ridges are located the longitudinal valleys, hollows or troughs 44, said ridges and troughs correspondingto the shape of the comb teeth of the comb 38. Where it is desired to have the ridges 43 spaced relatively far apart, in such case the comb teeth 41 are employed while if it is desired to have said ridges 43 closely spaced, the comb teeth 40 are employed. If, in either case, a stone or other hard particle should accidentally be drawn into the space between the comb 38 and the conveyor belt,. then said comb together with its safety door 33 swings forwardly and upwardly about the hinge pivot 32 and thereby allows the same to pass through, whereupon the comb and door are returned to their original position under the'influence of the springs 34.

Arranged forwardly of the charging box 15 is a pair of longitudinal brackets 45 constructed of rolled Z bar stock extending up from the main frame 10 of the machine and secured thereto by bolts 49 (see Figs. 4 and 1). Arranged upon the upper faces of said brackets 45 and. extending across and above the conveyor 13 is a tank or vat 46 which is adapted to be filled to a constant level with a viscous material or aggregate 52. This viscous vat 46 is supported at all four corners by adjusting screws .47 which are threaded through side flanges 48 of said vat and bear with their lower ends against the upper flat faces of the Z brackets 45. 'By suitably screwing in or out these adjusting screws 4'7, said viscous vat may be tilted to any desired position, after which the adjustment is locked in place by lock nuts 50 and the vat pressed downwardly and firmly in place by a pair of clamping screws 51, whose shanks pass through the flanges 48 of said vat and whose lower ends are threaded into the brackets 45. The vat is adapted to be supplied with viscous material 52 from a suitable supply pipe 53, the level 54. being maintained constant by the usual and well 58 which engages with an endless chain belt 60,

the latter being power driven from any suitable source, preferably in synchronism with the belt conveyor 13. Secured to said feed shaft. 57 intermediately of the longitudinal side walls of the viscous vat 46 is a viscous feed paddle wheel 61 having an annular, coaxial row of feeding blades 62 which successively dip down intothe viscous material 52 and successively pick up a quantity thereof and discharge the same in the form of slugs or windrows 63 onto an equalizing plate 64 which extends transversely of the machine and is inclined downwardly and forwardly. This equalizing plate is secured to the front wall of the viscous vat 46 so that the slope of said plate may be adjusted either by turning the adjustment screws 47 up or down, or said plate may be adjusted, independently of said vat, by merely bending it up or down until the desired slope is obtained. This equalizing plate 64 operates to make more uniform the ribbon 65 of viscous material 52 which is deposited upon the corrugated ribbon 39 of dry, pulverized gypsum which is moving in a forward direction beneath said equalizing plate. The action whereby this result is obtained is as follows: The slope of the equalizing plate 64 is such that the slugs or windrows 63 of viscous material 52 which are discharged successively upon the upper end of said plate by the paddle wheel 61 are caused to slide down upon said equalizing plate 64 at a speed slightly greater than the speed of travel of said conveyor. The result is that these windrows 63 are not discharged individually from the equalizing plate 64 but are thrown one upon the other and thereby caused to impinge upon each other and to merge together at the lower end of said equalizing plate 64, so

that the ribbon 65 of viscous material is of approx- I I The dry, pulverized gypsum 20 is fed at a syn'-, chronous rate of speed from the screw conveyor the teeth 41 or 40 of the comb 38 so as to form a corrugated ribbon 39 of dry, powdered gypsum 20 having longitudinal ridges 43 and intermediate,

'21 into the charging box 15 from whence it is carried along upon the conveyor 13 under either longitudinal troughs 44. Said charging box 15 conveyor belt by means of wing nuts 30. Any

hard article passing under the comb 38, and tending to become jammed, causes said comb together with the safety door 33 to swing up and back about the hinge 32 and to be returned to normal position by the springs 34 as soon as said hard article has passed through. Said comb 38 is vertically adjustable by means of the bolts 3'7.

Viscous material 52 is maintained at a constant level in viscous vat 46 which is supplied through a supply pipe 53. .Regulated successive quantities of said viscous material are discharged from said v'at 46 by the paddle wheel 61 upon the inclined equalizing plate 64 from which is discharged a ribbon of viscous material of uniform thickness. This material contains a considerably higher percentage of water than the ribbon 39 of dry gypsum which itrests upon, and, as the length of the belt conveyor 13 is very considerable and its speed of travel relatively slow, it follows that a considerable period of time is permitted for the moisture in said viscous material ribbon 65 to pass downwardly (under the combined action of gravity and capillary absorption) into the dry gypsum ribbon 39 below. The corrugated upper face of said dry gypsum ribbon is effective in increasing the area of contact between the two ribbons of material, and hence in increasing the speed of liquid absorption In this manner, the liquid content of the viscous material is reduced and the liquid content of the dry gypsum increased. It should be particularly noticed that this transfer of moisture is accomplished without mechanically mixing or stirring up said wet and dry ingredients because such a stirring up would cause the material toball up" around individual pieces ofthe viscous material as nuclei for said balls. After the mixing machine of the present invention has thus mix -,viscous material and the dry gypsum to the extent of mixing its-water content more uniformly, the resultant and still stratifiedmixture is passed to an ordinary ball mill or other suitable mixer which completes the mixing operation and brings about a condition whereby not only is the water content uniform but the consistency of all the other ingredients is also caused to be uniform. Such a final mixing in a ball mill or the like is not essential if the strata or ribbons of viscous and dry material are sufficiently thin, but in actual practice, it is preferred to have these ribbons relatively thick and to only ensure that the water content is made sufilciently uniform throughout the entire mass as not to ball up when discharged into an ordinary mechanical mixer.

when it is desired to clean the conveyor belt 13, the same may be reversed in its direction of movement and the wing nuts 24 loosened and the gypsum charging box 15 elevated. "This dumps the entire charge of dry ypsum on said belt conveyor, the gypsum then being discharged over the tail end of said conveyor.

It will be seen from all of the foregoing that the principle of operation of the herein invention is unique and fulfills a hitherto unaccomplished need in mixing ingredients, one of which is dry and more or less powdery and the other of which is either moist or otherwise sticw and viscous. The fullest advantages of the invention are obtained when there is an actual transfer of liquid from the one ribbon of material to the other, but the invention is by no means confined to suclf a water transfer system. The very bringing into contact of two ribbons of different "materials constitutes all by itself a mixing operation, the thoroughness of which is proportional to the thinness of said ribbons.

, such a change in the moisture content of said .layers; and means for thereafter removing both of said layers of material from said surface.

. 2. A mixing machine comprising means for spreading a corrugated layer of relatively dry material upon a moving surface means for superim- Lposing thereon a layer of relatively moist material, the percentage of' moisture in said moist material being suiflciently high to cause a flow of moisture from said layer of moist material down into said layer of dry'material and -the time, during which said layers are in contact with each other, being sufllciently long to effect such a' 7 change inthe moisture content of said layers;

and means for thereafter removing both of said layers from said surface.

3. A mixing machine comprising an endless belt; a comb arranged transversely abovesaid belt; means for supplying a dry material against the upper face of said comb so as to produce a corrugated ribbon of saidmaterial; means for spreading a ribbon of moist material upon said first named ribbon at a point to the rear of said comb, the percentage of moisture in said moist material being sufficiently high to cause a flow of moisture from said ribbon of moist material down into said ribbon of dry material and the l time, during which said ribbons are in contact with each other, being sufllciently long to efiect such a change in the moisture content of said layers; and means for removing both of said rib-v bons of material from said belt.

4. A mixing machine comprising an endless belt; a hinged comb arranged transversely above said belt; means for supplyinga dry material against the upper face of said comb so as to produce a corrugated ribbon of said material; means i for spreading a ribbon of wet materialupon said first named ribbon at a point to the rear of said comb, said materials being in contact with each other a sufiicient length of time to permit moisture to flow down from the wet material into the dry material; and means for removing both of said ribbons of material from said belt.

5. A mixing machine comprising an endless belt; a comb arranged transversely above :said belt; means for vertically adjusting said, comb; means for resiliently holding said cor'nb in place; means for supplying a dry material against the upper face of said comb so as to'produce a corrugated ribbon of said I material; means for spreading a ribbon of wet material upon said first named ribbon at a point to the rear of said comb, said materials being in contact with each other a suillcient length of time to permit moisture to flow down from the wet material into the dry material; and means for removing both of said ribbons of material from said belt. v

6. A mixing machine comprising an endless belt; a comb having comb teeth of different form on its opposite edges and arranged transversely above said belt; means for supplying a dry material against the upper face of said comb so as to produce a corrugated ribbon of said material; means for spreading a ribbon of wet material upon said first named ribbon' at a point to the rear of said comb, saidmaterials being in contact with each other a sufllcient length of time to permit moisture to flow down from the wet material intothe dry material; and means for removing both of said ribbons of material from 7. A mixing machine comprising means for supplying a ribbon of dry material to a moving surface; a vat; means for supplying a viscous material to said vat; means for discharging successive quantities of said viscous material from said vat; an inclined unifying slide adapted to receive said successive discharges of said viscous material and to deposit the same.upon said ribbon of dry material; and means for removing said dry and said viscous material from said moving surface.

8. A mixing machine comprising means for supplying a layer of dry material to a moving surface, a vat, means for supplying a viscous,

material to said vat, means for discharging viscous material from said vat, and an inclined slide adapted to receive said viscous material and to deposit the same upon said layer of dry material. 9. A mixing machine comprising a'moving belt,

a; comb arranged transversely above said belt,

l V I means for supplying material against said comb to produce a corrugated layer of material, and means for spreading a viscous material upon said corrugated layer at a point to the rear of said comb.

10. A mixing machine comprising a moving belt, means for supplying a layer of material on said. belt, means for forming longitudinal corrugations in said layer of material, and means to the rear of said corrugating means for spreading a layer of viscous material upon said cormgated layer, said viscous layer extending trans versely of the corrugations.

11. A mixing machine comprising a conveyor having a receiving and a discharge end, means at said receiving end to discharge and spread a layer of dry material on said conveyor, a moist material discharging and spreading means spaced from said dry material discharge means for depositing a layer of moist material upon the passing layer of dry material on said conveyor, said conveyor extending a great distance from said second discharge means to its discharge end whereby a slow exchange or moisture is eflected between said layers before being discharged from said conveyor.

12. A mixing machine comprising a conveyor having a receiving end and a discharge end, means at said receiving end to discharge and spread a. layer of dry material on said conveyor, means comprising a hopper having a bottom and a discharge orifice arranged above "said conveyor for gently discharging and spreading a layer of moist material upon the passing layer of dry material on said conveyor, said conveyor extending a great distance from said last means to its discharge end whereby a slow exchange of moisture is effected between said layers before being discharged from said conveyor. 

